1. Field of the Invention
The present invention relates to a dispersion-stabilizing agent for inorganic powder in an oily material. More particularly, the present invention relates to a dispersion-stabilizing agent for inorganic powder in an oily material, which can disperse an inorganic powder in an oily material within a short period of time and can stabilize the dispersion over a long period of time.
2. Related Background Art
Dispersion of inorganic powder in an oily material are used in various industrial fields. A familiar example is a paint, in which a pigment and a filler are dispersed in a resin solution. Recently, dispersions of inorganic powder in hydrocarbon oils have come to be used for abrasives and fuel tank cleaning liquids.
In such a dispersion in oil, a dispersion-stabilizing agent is generally employed for dispersing an inorganic powder into the oil. U.S. Pat. No. 4,354,872 discloses use of an alkanolamide, a fatty acid and magnesium lauryl sulfate for dispersing magnesium oxide in hydrocarbon oil.
The dispersion-stabilizing agents are required to be capable of dispersing the inorganic powder rapidly in an oily material within a short period of time, and are required simultaneously to be capable of stabilizing the inorganic powder without precipitating the inorganic powder over a long period of time, and to be capable of easily re-dispersing the inorganic powder even when it has precipitated.
Various dispersion-stabilizing agents have been reported to meet the requirements. However, none has satisfied simultaneously the above-mentioned two requirements.